A well‐developed 86 m‐thick Cenozoic sedimentary succession in the Matanomadh area, western Kachchh, was studied to assess the stratigraphic positions of different units, ascertain depositional environments, and the degree of climatic controls over time depositional processes. Age‐diagnostic nannoplankton species Cyclicargolithus floridanus (46.29–12.1 Ma), Reticulofenestra dictyoda (53–30.8 Ma), Reticulofenestra minuta (50.5–2.59 Ma) and foraminiferal species, for example, Orbulinoides beckmanni (41–39.5 Ma) found across studied units envisage the stratigraphic age and palaeoenvironment. CaO with strong negative elemental correlation, binary/ternary discriminant tectonic and depositional regimes cross‐plot from units indicate the biogenic origin of limestones and shales were formed in typical passive, marginal, shallow littoral settings with plausible detritus influx from Deccan basaltic provenance. Total organic carbon with TE‐REE respectively connotes a sedimentation process in a nearly consistent open shallow marine, locally transient semi‐restricted marginal basin in a tropical‐equatorial region. Furthermore, principal component analysis (PCA) of weathering indices based on elemental abundance and X‐ray diffraction data of clays deterministically suggest with empirical relation between humid tropical climate‐induced weathering and fluctuant terrestrial influx. Palaeoredox indices with biological data demonstrate localized redox‐stratified conditions. However, coherent signatures of the global events such as Eocene Thermal Maximum‐2, Middle Eocene Climatic Optimum, and Mid Miocene Climatic Optimum can be traced and validated by synthesizing geochemical data for direct/indirect estimation of sediment routing, rainfall (αAlMg and αAlCa) and climate proxies (PCA), productivity indices (Babio, Cubio and Nibio), and localized periodic oxic‐dysoxic environment (V/Cr, U/Th, Ni/Co) from core samples.

The potential of reflectance spectroscopy to infer the paleoecological and depositional evolution of different micro and macro invertebrate fossils has been evaluated by analyzing their reflectance spectra within the spectral domain of 350–2500 nm using the FIELDSPEC3 spectroradiometer. Mineralogical information derived from the rapid and non-destructive spectral analysis has been substantiated using concurrent mineralogical data from conventional geochemical analyses. The diagnostic Fe-crystal field effect induced spectral features are identified on the representative spectra of different benthic foraminifera. These spectral features are resulted due to the incorporation of Fe during the biomineralization process. These features are absent in planktic foraminifera. The encrustation of Fe-oxides is inferred to be responsible for imprinting the Fe-crystal field feature in the spectra of micro and macrofossils at 900–1200 nm. Vibrational spectral features of the Al–OH bond are also identified. Both of these features are an indicator of post-depositional diagenetic history. The presence of Al and Fe in macrofossil shells is also believed to be related to ecological conditions as these elements are biogenically incorporated during shell formation. This study reveals the value of reflectance spectroscopy to infer ecological behavior and post-depositional environment of different organisms.

The present work is pursued on the benthic foraminiferal groups obtained from NGHP core samples of the western Bay of Bengal to understand the variations of paleoceanography and Indian Summer Monsoon (ISM), as well as socio-economic changes in ancient India. Benthic foraminiferal AMS 14C dating reveals that the studied interval spans between 335 BC and 1355 AD, covering the history of the last 1690 years. We compared foraminifera group counts with published isotopes, sunspot number, summer monsoon index, hematite-stained grain, Al/Ca, 14C data sets. Angular Asymmetrical Benthic Foraminifera, infaunal, and dysoxic groups exhibit declining trends with warm, humid intervals with intensified ISM signature from 335 BC to 406 AD (Roman Warm Period) and from 787 to 1202 AD (Medieval Warm Period). The Increasing trend of the above foraminiferal groups captures the signature of weak ISM from 406 to 787 AD (Dark Age Cold Period) and from 1202 to 1355 AD (Medieval Warm Period and Little Ice Age Transition). Whereas rounded symmetrical benthic foraminifera, epifaunal, and oxic groups show a reverse relation with the abovementioned groups. Spectral analysis of foraminiferal groups shows significant periodicities of 563/561, 450, 321, 281/250, 22/27, and 17/16/15 years, corresponding to various solar cycles. This research uncovers the relationship between solar activity and monsoonal changes, which influenced India’s economic growth and played a crucial role in the establishment and demise of successive dynasties throughout the Indian subcontinent during the late-Holocene.